Pertinent spatio-temporal scale of observation to understand suspended sediment yield control factors in the Andean region: the case of the Santa River (Peru)

Abstract

Abstract. Hydro-sedimentology development is a great challenge in Peru due to limited data as well as sparse and confidential information. This study aimed to quantify and to understand the suspended sediment yield from the westcentral Andes Mountains and to identify the main erosioncontrol factors and their relevance. The Tablachaca River (3132 km 2 ) and the Santa River (6815 km 2 ), located in two adjacent Andes catchments, showed similar statistical daily rainfall and discharge variability but large differences in specific suspended-sediment yield (SSY). In order to investigate the main erosion factors, daily water discharge and suspended sediment concentration (SSC) datasets of the Santa and Tablachaca rivers were analysed.Mining activity in specific lithologies was identified as the major factor that controls the high SSY of the Tablachaca (2204 t km 2 yr −1 ), which is four times greater than the Santa's SSY. These results show that the analysis of control factors of regional SSY at the Andes scale should be done carefully. Indeed, spatial data at kilometric scale and also daily water discharge and SSC time series are needed to define the main erosion factors along the entire Andean range.

The impact of extreme El Niño events on modern sediment transport along the western Peruvian Andes (1968–2012)

“…As a result, annual runoff and SSY in the studied stations have moderate to strong positive correlations (0.5 < r < 0.9; p-value > 0.05). Moderate correlations (0.5 < r < 0.75) are found in the Poechos (watersheds 6, 7 and 10), Gallito Ciego (watershed 12) and El Platanal reservoirs (watershed 18), as well as in areas impacted by mining and with lithology singularities (watershed 14) 32 . Overall, our results indicate that spatial variations of precipitation and runoff at the watershed scale mainly determines the spatial changes in SSY during normal years.…”

Spatio-temporal patterns of the effects of precipitation variability and land use/cover changes on long-term changes in sediment yield in the Loess Plateau, China

“…Differences in catchment characteristics, including land use/cover, soil properties, and topography, as well as precipitation characteristics, are clearly the reason for the spatial patterns in the precipitation-sediment yield relationship (Morera et al, 2013;Mutema et al, 2015). The lower vegetation cover was the main reason for the greater effects of precipitation on sediment yield in the northwestern part.…”

Sediment load trends in the Magdalena River basin (1980–2010): Anthropogenic and climate-induced causes

“…Studies analyzing physical and anthropogenic controls on sediment yield in Andean catchments have shown that sediment yield is controlled by (i) runoff and maximum water discharge in the Magdalena River basin (Restrepo et al, 2006a); (ii) rainfall variability along the eastern range of the Andes from Ecuador to Bolivia (Pepin et al, 2013); (iii) cover, soil types, and road networks in the Paute River in Ecuador (Molina et al, 2008(Molina et al, , 2015; (iv) mining activity in specific lithologies in the western central Andes of Perú (Morera et al, 2013); (v) lithology and slopes in the Bolivian Andes (Aalto et al, 2006);and (vi) slope and runoff in Chilean catchments from northern Chile to southern Patagonia (Pepin et al, 2010). Despite the importance of these studies on understanding the main natural controls on sediment yield in Andean basins, they did not assess the combined effect of natural and human-induced activities (e.g., deforestation) on temporal trends in sediment yield.…”